High Frequency Transduction by Phage Hybrids between Coliphage phi 80 and Salmonella Phage P22

摘要

U Phi 80immP22dis, a hybrid between phi 80 and p22, carries all the late genes of phi 80 and most of the P22 early region including the immC and immI bipartite immunity loci. The presence of the immI region allows this hybrid to grow on lysogens of phi80 immP22 hybrids which have the immC locus, but not the immI locus. In addition to these P22 immunity regions phi80immP22dis contains the P22 att marker so that the prophage can be inserted into the chromosomal P22 attachment site adjacent to the proA-ProB region of the host. Unlike its phi80 parent which performs specialized transduction of the trp region, phi80immP22dis transduces markers located adjacent to its attachment site to Escherichia coli K12 recipients at high frequencies (0.3% for argF and 0.18% for proA). Induction of phi80immP22dis lysogens yields new hybrid phage clones which have incorporated E. coli K12 chromosomal segments in place of the P22 immI to att segment. Having lost the immI region, the new hybrids, no longer grow in phi80immP22 lysogens. These new hybrids, termed phi80immP22dis, possess specialized transducing properties, transferring the argF and proA markers at higher frequences (21% for argF and 12% for proA) than previously obtained with the phi80immP22dis phage. (Author)